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introduction

What is MongoDB?​

  • MongoDB is document based NoSQL Database. Most widely used NoSQL Database in the world.
  • Stores Data in JSON like documents. (BSON)
  • Very flexible structure to store the data
  • Large amount of data can be easily managed.
  • It is being used by well known companies like google, adobe, cisco SAP, eBay.

SQL VS NoSQL​

SQL databases are vertically scalable, while NoSQL databases are horizontally scalable. SQL databases are table-based, while NoSQL databases are document, key-value, graph, or wide-column stores. SQL databases are better for multi-row transactions, while NoSQL is better for unstructured data like documents or JSON. sql-vs-nosql.jpg

SQL Structure​

The structure of SQL (Structured Query Language) includes tables, columns, rows, and SQL queries. SQL is a programming language that allows users to manage and manipulate relational databases.

Tables​

  • The foundation of SQL, tables store data in rows and columns
  • Each table has a physical representation of data

Columns​

  • The fields in a table that define the types of data stored
  • Each column has a specific data type, such as INTEGER, VARCHAR, or DATE

Rows​

  • Each row contains all the information about a single record

SQL queries​

  • The basic structure of an SQL query includes a SELECT clause, a FROM clause, and an optional WHERE clause
  • Other components of an SQL query include GROUP BY, ORDER BY, and LIMIT

SQL commands​

  • Data Definition Language (DDL) commands are used to build, change, and delete database structures
  • Data Manipulation Language (DML) commands are used to store, update, remove, search, and retrieve information from the database

MongoDB Terms​

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MongoDB Collection Example​

{
  "_id": ObjectId("63fce3a9e72c4b3a9b9e1b34"),
  "title": "1984",
  "genre": "Dystopian",
  "publishDate": ISODate("1949-06-08T00:00:00Z"),
  "author": {
    "firstName": "George",
    "lastName": "Orwell",
    "birthDate": ISODate("1903-06-25T00:00:00Z"),
    "nationality": "British"
  },
  "availability": {
    "totalCopies": 5,
    "borrowedCopies": 2
  },
  "borrowRecords": [
    {
      "memberId": ObjectId("63fce4a9c71a4b8f9d1c3e1f"),
      "borrowDate": ISODate("2023-01-15T00:00:00Z"),
      "returnDate": null
    },
    {
      "memberId": ObjectId("63fce4c2d92a4b5f7e1f3e21"),
      "borrowDate": ISODate("2023-01-20T00:00:00Z"),
      "returnDate": ISODate("2023-02-01T00:00:00Z")
    }
  ]
}

Explanation​

  1. Document Structure: MongoDB uses JSON-like documents (key-value pairs) stored in collections.
  2. Nested Objects: The author and availability fields are nested objects.
  3. Array Fields: borrowRecords is an array of objects representing borrowing transactions.
  4. Data Types: MongoDB supports ObjectId, ISODate, numbers, strings, etc.